The M-140 Offset Carrier is self guiding with the flanged wheel design. The 4 rollers are made of Delrin, an engineered plastic with excellent properties for use as bearings. The steel axle is machined to a 30 micron finish for smooth rolling under load. The 9.5" long body is made of 1/8" thick 6061T-6 aluminum alloy. Two 3/8" diameter holes 8" apart on the body with another hole 4" further on the offset arm for attaching s-hooks or trim chains.